Lavender Foal Syndrome

Genetic Testing for Lavender Foal Syndrome

Lavender Foal Syndrome (LFS) is an inherited lethal disease of horses. The inheritance pattern suggested a single gene defect inherited in an autosomal recessive manner but this had not been systematically investigated. Recent whole genome SNP analysis of LFS-linked horses has led to the identification of a single nucleotide deletion in exon 30 of the Myosin Va Gene responsible for LFS.1 All affected foals tested were homozygous for the mutation (both copies of the gene had the mutation), while all available parents were identified as heterozygotes (one gene had the mutation, one gene had a normal sequence). The deletion creates a premature stop codon and results in the truncation of a highly conserved protein product involved in intracellular vesicle trafficking. Prevalence of heterozygotes in the Egyptian Arabian population is estimated at approximately 10% and the recessive inheritance pattern has been supported.¹

TESTING INFORMATION

An assay to detect the deletion associated with LFS has been developed and is now available through the Animal Health Diagnostic Center at Cornell University. Testing of breeding animals is recommended to avoid breeding carriers to each other. The assay generally requires the submission of hair roots pulled from the mane or tail. Pulled hair samples should be trimmed to a 4 inch length and taped to a hair sample sheet. Samples from each horse should be placed in individual envelopes, sealed, and attached to a LFS submission form. Other samples may be tested, including EDTA whole blood samples collected in lavender topped blood tubes. For more specific information about the test, see the expanded information sheet.

Please be sure to also fill out the requested information on the sample submission form using a submission form for each horse. Multiple envelopes may be shipped together in the same outer package. Hair samples can be shipped by mail (USPS) or courier (UPS, FedEx). Care should be taken to keep hair samples dry. EDTA whole blood samples and tissue samples packed in a clean leak-proof container should be shipped in a thermal cooler with freezer packs by overnight courier. The LFS mutation has not been detected in breeds other than the Arabian and testing for this mutation in horses with no Arabian breeding may not be appropriate. Horses with unknown pedigrees can be tested.

Testing is readily available for horses residing outside the USA from hair root samples. Hair samples can be shipped to the USA without a permit required. EDTA whole blood samples can also be tested, but shipment of these samples to the laboratory requires the use of a USDA permit. There may not be permits available for the import of blood specimens from some countries. Please contact the laboratory (Lisa Bowen-Laue; 607-253-3938) for the appropriate permit if you wish to submit EDTA whole blood for LFS testing from outside the USA.

A completely filled out LFS assay submission form must accompany each sample. The cost of the test is $45.00 in addition to a $2.00 accession fee that will be charged for each horse tested. Payment must accompany samples unless samples are submitted by a licensed veterinarian. Payment may be made by VISA, Master Card, Discover, or American Express. Checks or wire transfers cannot be accepted. Please submit credit card information using our credit authorization form. Samples submitted by a veterinarian with an established AHDC billing account will be billed at the end of the month in which the results are finalized. Veterinarians submitting samples for LFS testing need to use the LFS submission form and hair sample sheet.

Results will be available within 10 business days of receipt. Stat testing can be requested, but must be arranged with the laboratory in advance. A stat fee of $150.00 per sample will be applied. Samples are treated as individual accessions to facilitate the reporting of single animal results. Results can be reported by Email, Fax or regular mail. Please indicate on the submission form how you would like your results reported.

REFERENCE

1. Samantha A. Brooks, Nicole Gabreski, Donals Miller, Abra Brisbin, Helen E. Brown, Cassandra Streeter, Jason Mezey, Deborah Cook, Douglas F. Antczak. (2010) Whole-Genome SNP Association in the Horse: Identification of a Deletion in Myosin Va Responsible for Lavender Foal Syndrome. PLoS Genet 6(4): e1000909. doi:10.1371/journal.pgen.1000909.